Metallurgy of zinc.



A. L. J. QUENEAU. METALLURGY OF-ZING. APPLICATION FILED DEG.17,1908.

L,114,036. Patented 00t.20,1914.

IZZIIZC fire Reducing PreZea/er Aye/12 Preheafer Eeduc/hy Fizmace V ['Mdmser v WITNESSES- I l/VVE/VTOB.

A TTORNE Y8 UNITED STATES PATENT cur os.

AUGUSTIN LEON JEAN QUENEAU, OF,TOB1RESDALE, PENNSYLVANIA, ASSIGNOR TO 7 QUENEAU ELECTRIC ZINC FURNACE COMPANY, OF PHILADELPHIA, PENNSYL- VANIA, A CORPORATION .OF DELAWARE,

METALLURGYOF ZINC.

Specification of Letters Patent.

Application filed December 17-, 1908, Seria1'No. 467,,98.6.

To all whom it may concern:

Be it known that I, AUcUsTIN 'Lr'ioN EAN QUEI'JEAII, a citizen of the Republic of France, residing at Torresdale, county of Philadelphia, and State of Pennsylvania, have invented certain new and useful Improvenrent's in Metallurgy of Zinc; and'I do,

hereby declare the following tobe a full, clear, and exact description of the invention, such as will enable others skilled in' the art to which it appertains to make and use the same.

The standard practice of today in the nized, but the many attempts tosupplant it have heretofore been unsuccessful. The inefiiciency of the process arises from the fact that the ore mixture must be heated to about of the retorts hardly more than thirty days.

The condensationof the zinc vapor also pr,e sents difficulties, andmuch of it'is collected as a metallic powder which must be redistilled, in order to becondensed tothe liquid state; H

In contrast to the standard practice above indicated, the present invention permits the treatment of the ores in receptacles of large size, adapted to contain a correspondingly large charge. Furthermore, it permits the thickness of the walls of the containing vesselto-be greatly increased and permits them to be made of a material more resistant to the action of slag than fire clay. Moreover, in the treatment of zinc ores containing sulfur it is not necessary, in order to adapt Patented Oct. 20, 1914;.

them to the uses of the invention, that they should first be .brought'to a ,sweet roast, inasmuch as the reduction of the .ores by means of iron, .or by means of lime and carbon, according to' the formulae can be readily effected, particularly in View of the fact that during the reducing openation, the reducing agents are brought into and intimate contact with the ore. lt is, therefore, desirable merely to roast the zinc sulfid ores to a sulfur content of five-"or six per cent., which can be brought about with a small expenditure of coal and, in fact, zinc ores in the raw .or unroasted condition may be treated in accordance with the invention.

Furthermore, in the practice of the invenv tion, zinc ores carrying copper, lead, iron, gold or silver can be commercially treated, andto particular advantage if to the zinc ores carrying gold or silver,some.copper ore is added toform a copper ,matte to take up the precious .metalsi In the present practice theeniployment of ores high in slag-formingelements corrosive to the fire clay walls of the retorts is avoided, as it is necessary to have the reduction residues presentina drypulverulent condition in orderto allow of their easy removal from the retorts, ,and for this reason alarge excess of reducing material is used to act' as a sponge, .holdin apart any slag- ,forming material. On t, e other hand, as

will appear fromthe description of the furnace, in the present instance,'it is necessary to have the residual products of the treated charge .in a highly "fluid state and of [a chemical composition having the minimum dissolving powerzfor zinc compounds. Itfollows,-therefore, that ores that are of anobjectionable chemical composition for the present practice but which are of low cost are highly desirable for the practice of the present invention. In the practice of'the invention it is also feasible to pre-heat the ore to a high temperature before admitting it into the reduction furnace, for instance, to

' pre-heat it toa temperature of say 1000 C.

This pre-heating of the ore may be attained in the ordinary roasting kilns, and is-incident to the roasting of the ores in such kilns; so that the-ore, after its sulfur content is'reduced to the low .limit incident to the roasting operation and is discharged from the kiln, may be discharged directly into the zinc-reducing furnace, or may be revolving the latter.

temporarily stored in a receptacle which will conserve or substantially conserve the high heat of the ore until the zinc-reducing furnace is. ready to receive it. Whether the high preliminary heat of the ore is an incident of the roasting operation or. is otherwise imparted to it, such; temperature is. higher than the temperature at which the coal or other reducing agent would burn in the air. For this reason, the mixing of the reducin agent with the ore should preferably'ta e place within the furnace itself.

Nevertheless, it will befound of advantage to also pre-heat the reducing agent, but at a temperature lower than that at which it would burn in the ,air, theore and the reducing agent being'char' ed separately into the reducing furnace an mixed therein by In carrying out the invention, it will be desirable to heat the interior of the rotary reduction furnace to a high temperature, by a gas and air flame, or the like, before admitting the furnace charge. To then maintain the reducing temperature during the subsequent reduction of theore and distil lation of the zincv therefrom a molten fluid resistor is employed, which is introduced into the furnacechamber, in such manner as to forma path for an electric current of such a character as to maintain the fluidity of the resistor and the high temperature necessary to carry on and completethe reducing operation, the surfaces of contact between the charge and the fluid resistor being constan-tly'renewed by reason of the rotative movement of the furnace chamber, thereby increasing the speed of the reaction.

The zinc vapors given off by the charge are;

received in condensers .of such construction and arrangement that the vapors are condensed therein to'the metallic liquid state, special provision being made for regulating and'maintaining the temperature conditions desirablefor the recovery of the zinc in this form.

A furnace Letters Patent 'No. 1,006,876, grantedto me under date of October 24, 1911, and I refer specifically thereto for the details of consuitable for-the purposes of the invention is illustrated in United States struction and the mode ofrope'ration appropriate to such a furnace.

In the drawing, hereunto attached, I have denser are preferably of the rotary type as indicated.

Speaking further of the, general operati on of the invention, it will be noted that the agitation of the contents of the furnace, due to the rotation,'1-esults in close and intima-te contact between the constituents of the furnace charge, thereby shortening the time required for the complete chemical action, and not only increasing the daily furnace capacity, but also increasing the heat efliciency 'of the furnace, as heat is radiated,- for a given charge, during a shorter space of time, so that the loss of radiated heat is correspondingly less. Furthermore, the rotation and agitation of the contents of the furnace result in the rapid attainment of an equilibrium of temperature throughout the mass of the charge,-and the rotation of the furnace, by constantly renewing the surface 'of the lining in contact with the heating medium, keeps the whole furnace at a high heat. Evidently, however, the upper part of the furnace will be at all times to some extent cooler than the lower part which containsthe molten resistor. This is a desirable feature, in that it keeps at a minimum the temperature of the'issuing gases and vapors, thus facilitating the condensation of the latter while keeping at a minimum the number of heat units carried away by the gases.

What I claim is 1. The method of extracting and recotien ing zinc from zinc ore, which consists in pre'-,,' heating sald zinc ore, separately charging 1 into a reducing furnace the ore in the preheatedstate and a reducing agent, inti'- .mately mlxlng them within the furnace,

subjecting the mixture to a reducing atm0sphere and. a reducing temperature with exclusion of air, thereby releasing the zinc the form of zinc vapor, and condensing said vapor. to the metallic state.

2. The method of extracting and recovering zinc from zinc ore, which consists in preheating said zinc ore to a temperature above that at which the reducing agent to be used would burn n air, separately charging lnto a reducing furnace the ore in the preheated state and a reducing agent, intimately mlxlng them wlthm the furnace, sub eCting the mlxture to a reducmg atmosphere, and a reducing temperature with exeluslon of 2111', thereby releasmg the zlnc in the form of zinc vapor, and condensing stud vapor to the metalhc state.

In testimony whereof I afiix my signatnre,

Witnesses:

JOHN C. PENNIE, LAURA B. PENIIELD, 

